Throttle valve control means



ay 17, 1938. w HOLDEN 2,117,421

THROTTLE VALVE CONTROL MEANS Filed July 24, 1934 INVENTOR; lVZZZmm 6.Holden;

. Ola/WW1 ATTORNEY.

Patented May 17, 1938 UNITED STATES PATENT OFFiCE Carter CarburetorCorporation,

New York,

N. Y., a corporation of Delaware pplication July 24, 1934, Serial No.736,641

1 Claim.

The present invention relates to an improvement in automobile engineaccelerator pedal control means, and it has for its principal object theprovision of means in conjunction with the pedal accelerator of anautomobile gas engine, whereby to permit of instant acceleration of theengine and to control the deceleration thereof to the desired degree,particularly but not exclusively while the engine is clutched to thegear drive means.

In modern automotive practice, the tendency is to build light weightautomobiles with heavy powered, high speed engines, and this tendency,while increasing the pick-up, speed and acceleration of automobiles,when the throttle valve of the engine carbureter is opened, also has theunpleasant tendency to decelerate the speed of the automobile sorapidly, when the foot is removed from the accelerator pedal, as to tendto throw the passengers forwardly out of their seats.

It is, therefore, amongst the objects of the present improvement topermit of instant acceleration of the automobile and to so control thedeceleration thereof, automatically, as to obviate the unpleasant rapiddeceleration of the vehicle.

Such variable engine speed control is mainly accomplished through athrottle valve located in the carbureter passage and is well knownpractice.

Therefore, in order to control the deceleration action of the throttlevalve, automatically, without interfering with the possibility ofinstant acceleration action of the throttle valve there has beenprovided, as will later be described in detail, a one way actingdash-pot throttle valve control, utilizing the liquid gasoline, from theusual carbureter float control chamber, as a liquid medium, tomeasurably control the dash pot plunger in its downward stroke, thus toprevent too rapid deceleration when the drivers foot is removed from theaccelerator pedal.

The foregoing, and other features of advantage will be apprehended asthe description herein proceeds, and it is obvious that modificationsmay be made in the structure herein, without departing from the spirithereof or the scope of appended claim.

In the drawing,

Fig. l is a reduced, perspective view of a gasoline carbureter havingthe throttle valve control means attached thereto in one form ofembodiment;

Fig. 2 is an enlarged side elevation of a. fragmented carbureter withportions broken away for better showing;

Fig. 3 is an enlarged side view of the lower intake end and floatchamber portion of the carbureter, with parts broken away or removed,showing the dash-pot throttle valve connection; and

Fig. 4 is a transverse section, enlarged, of the dash-pot, showing thedash piston in its lowermost, throttle closing position.

As the carburetor is of well known down-draft construction only suchmain details thereof as cooperate with the present improvement will bedescribed to aid in a proper understanding of the function of theinstant improvement.

The carbureter, Fig. 3 as partially shown comprises a body formed with afastening flange 3 attached to the throttle valve port portion I, whichlatter is surmounted by the Venturi passage portion 2. To one side ofthe Venturi portion 2 is located the fuel float chamber 4, as in Figs.1, 2 and 3.

The throttle valve port portion I has a passage way, shown dotted at 28,Fig. 2, and this passage is traversed by a rotatable throttle valveshaft l8, which carries and operates the usual butterfly, or throttlevalve disc 19, for variably controlling the port 20, and thus controlthe speed of the engine.

One end of the shaft 18 has affixed thereto, by a pin p, a lever arm I?and this in turn mounts a foot pedal operated lever operating rod 15,Figs. 1, 2 and 3, which latter, as in Fig. 1 has its other endoperatively connected to one arm 24 of a crank arm which is pivoted at25 to a bracket 25, the latter being rigidly connected and fulcrumed tothe manifold M. The other end 21 of the crank arm is operativelyconnected to a yoke end 29 at 28, said yoke end being fixedly mounted toa reciprocable push rod 30. Rod 30 is operatively connected at itsopposite end, at 32 Fig. 1, to one end of a rock arm 33, said arm beingpivotally mounted and fulcrumed at 34 to a bracket fixed to theunderside of dash D.

The other end of arm 33, as at 35, is operatlvely connected to a pushrod 31, with the opposite end of push rod 31 being operatively connectedat 36 to an accelerator pedal 31 which is pivotally connected in theusual manner through and to the upper face of foot board of dash D at3B.

The foregoing described foot operated means to cause operation of thethrottle valve I9, is a characteristic construction, well known in thisart.

The throttle valve control comprises the dash pct 0 shown in section inFig. 4, and is shown as having a closed bottom, a threaded open upperend closed by a threaded cap plug 8, said plug mounting a bored packingnut 9, which surrounds the piston rod ill, for reciprocal movementthereof, with its leather cup piston, generally denoted by H, said cuppiston being constructed in the known manner.

The upper end of the piston rod 10' may carry an integral eye Iii, foroperatively receiving the upper integral arm H of a reciprocating rodl2, the lower end of which rod 12 is operatively connected to the rocklever I! at 13, Fig. 2. Rocking of the lever I! upwardly by acceleratorpedal 36, causes the piston H to rise to the dotted position I, Fig. 4.

At its mid-portion the dash-pot has a tubular connection 5, connected toits boss 23, the other end of 5 being connected into the float chamber4, at 5, Fig. 3, at about the normal gasoline level, as controlled bythe usual float cut-ofi not shown, and liquid gasoline G flows into thedash pot C through tube 5 and thus keeps tube 5 filled to float level Jwith gasoline, which acts as the fluid decelerant when piston H startsdownwardly, under influence of spring 3|.

It will further be noted that the dash-pot cylinder C, at or about itslower end A, is a normal, straight cylindrical fit with the periphery ofthe piston H, and flares outwardly and upwardly along a distance B, andfrom thereon is of larger, constant bore, to its upper threaded end,thus providing for a sequentially increasing piston clearance, on theupstroke of the piston, for rapid acceleration or deceleration controlof valve throttle l9; and also providing for a sequential retardationaction on the piston, for decreasing the speed of the piston upon thedown stroke under the action of spring 3|, such decreasing speed beingof increased ratio as the piston H descends into the graduallydecreasing piston cylinder area.

The piston cup may be provided with an extremely small vent hole L, asin Fig. 4, to gradually permit the escape of fuel from the chamber underthe cup washer as the piston H approaches its final closed position.

Various structural details of means of embodying the dash-pot controlmay be substituted for the structure herein disclosed and still permitof fast, accelerating piston movement and automatic, gradually retardeddeceleration movement of the piston and its appurtenant throttle valve,during the last stage of the throttle closing movement.

From the foregoing it will be noted that as in Fig. 4, the cylinder C isdecreased progressively in nominal inside diameter from the top to thebottom, as viewed in Fig. 4, being larger at the top and, at the bottombeing an operative fit with the piston H, so that while the piston maybe rapidly moved upwardly, its downward movement is gradually retardedprogressively until the piston reaches the upper limits of position A,whereupon the tighter fitting of the piston H, causes the vent L tooperate to pass liquid to the upper chamber above the piston, thusfurther progressively decreasing the piston movement and accordingly thethrottle valve closing speed. In this manner the engine speed isgradually reduced, progressively, to its slowest speed of rotation.

Having thus described the invention, what is claimed is:

In combination with an internal combustion engine carburetor having athrottle valve and a constant level chamber, manual means for openingthe throttle valve, a spring for closing the throttle valve, and meansfor resisting movement of said throttle valve comprising a dash potcommunicating with said constant level chamber, and a cup-shaped pistonin said dash pot permanently connected to said throttle valve, saidpiston including a relief vent, said dash pot having a reducedcylindrical end portion shaped to snugly receive said piston during itsmovement therein, the open end of said cup-shaped piston facing thereduced end portion of said cylinder, said relief vent permitting thetravel of said piston at a substantially predetermined constant rate insaid reduced cylindrical end portion under tension of said spring, andwalls tapered away from said reduced cylindrical end portion to permit avarying rate of movement of the piston toward said end portion.

WILLIAM C. HOLDEN.

